Monthly Archives: April 2019

The photoplethysmogram (PPG) is a signal that measures changes in blood volume in some part of the body (e.g. the fingertip) by shining light into the skin and detecting small changes in the level of light absorption that occur due … Continue reading →

This circuit combines a simple audio amplifier (based on an LM358 opamp) with an Arduino Nano to facilitate the detection of clapping sounds or blowing on the microphone. This is my breadboard circuit: I actually used a loudspeaker for my … Continue reading →